This application is based on Patent Application No. 49805/1998 filed on Mar. 2, 1998 in Japan, the content of which is incorporated hereinto by reference.
1. Field of the Invention
The present invention relates to a device for monitoring images for specific types of patterns by analyzing video such as television pictures; more specifically the present invention relates to a device, method and recording medium for video inspection suitable for detecting images which contain periodic patterns of high contrast such as striping, checker, concentric, radial, or swirl patterns, covering more than a predetermined area.
2. Description of the Prior Art
It is known that images containing periodic patterns, such as striping, checker, concentric, radial, or swirl patterns having high contrast, may induce seizures when viewed by a photosensitive person.
In order to detect images (video frames) containing such patterns as striping, checker, concentric, radial, or swirl patterns from within a video sequence, an inspector either had to visually check the actual video displayed on a display device (a monitor) or to visually check a display on a waveform monitor.
Detecting images containing such patterns as described above by visually checking takes much time. The inspector(s) may also potentially be affected in his/her health by viewing video including the type of pattern forms mentioned above. Furthermore, this may cause a problem in that different inspectors may have different judgements on the same subject by the nature of personal error or variation.
An object of the present invention is to provide a device, method and recording medium for video inspection capable of automatically detecting images displayed in high contrast with patterns of specific forms contained in video pictures.
In accordance with the present invention, the video inspecting device provides input means for inputting a video subject to be inspected; image analyzer means for analyzing images in each frame of the inputted video subject with respect to both contrast and spatial frequency thereof; image processor means for computing, according to the result of the image analysis, a ratio between the entire image area and the part of image in which the intensity of the contrast and the frequency range of the peak values of the spatial frequency are out of allowable tolerance range respectively; and decision means for determining that the image in a frame is of the specific class to be detected if the computed ratio is not within the allowable tolerance range.
In accordance with the present invention, the video inspecting device may further comprise output means for outputting the result of decision from the decision means.
In accordance with the present invention, the video inspecting device may further comprise means for replacing the specific class of image included in the video subject with a substitute image or images, if the specific class of image to be detected is detected by the decision means.
In accordance with the present invention, the video inspecting device may further comprise means for eliminating the specific class of image included in the video subject, if the specific class of image to be detected is detected by the decision means.
In accordance with the present invention, video output from a video display device may be inputted to the video inspecting device as the video subject to be inspected.
In accordance with the present invention, video output from a video playback device may be inputted to the video inspecting device as the video subject to be inspected.
In accordance with the present invention, video output from a TV game machine may be inputted to the video inspecting device as the video to be inspected.
In accordance with the present invention, the frame is divided into a plurality of blocks, the image analyzer means performs the image analysis for each of the blocks, the image processor means determines whether or not each of the results of the image analysis is within the allowable range, and the ratio between the total area of the blocks that have been determined not to be within the allowable range and the area of a frame may be computed as the ratio of the part of image being out of the allowable range to the entire image.
In accordance with the present invention, a video inspection method provides the steps of inputting a video subject to be inspected, image analyzing each of the frame images of the inputted video with respect to both contrast and spatial frequency thereof; computing, according to the result of the image analysis, the ratio between the entire image area and the part of image in which the intensity of the contrast and the frequency range of the peak values of the spatial frequency are out of allowable tolerance range respectively; and determining that the image in the frame is of the specific class one to be detected if the computed ratio is not within the allowable tolerance range.
In accordance with the present invention, the video inspection method may further comprise the step of outputting the result of decision from the decision means.
In accordance with the present invention, the video inspection method may further comprise the step of replacing the specific class of image included in the video subject with another prepared substitute image or images if the specific class of image to be detected is detected.
In accordance with the present invention, the video inspection method may further comprise the step of eliminating the specific class of image included in the video subject, if the specific class of image to be detected is detected.
In accordance with the present invention, the video inspection method may further comprise the step of inputting video output from a video display device as the video subject to be inspected.
In accordance with the present invention, the video inspection method may further comprise the step of inputting video output from a video playback device as the video subject to be inspected.
In accordance with the present invention, the video inspection method may further comprise the step of inputting video output from a TV game machine as the video subject to be inspected.
In accordance with the video inspection method of the present invention, the frame is divided into a plurality of blocks, the video inspection method may further comprise the step of performing the image analysis for each of the blocks, determining whether or not each of the results of the image analysis is within an allowable range, and computing the ratio between the total area of the blocks that have been determined not to be within the allowable tolerance range and the area of the frame as the ratio of the part of image being out of the allowable tolerance range to the entire image.
In accordance with the present invention, a recording medium is provided which is equipped in a video inspection device and on which a program readable by a computer is stored, the program provides the steps of inputting a video subject to be inspected; analyzing images in each frames in the inputted video with respect to both contrast and spatial frequency thereof; computing, according to the result of the image analysis, the ratio between the entire image area and the part of image in which the intensity of the contrast and the frequency range of the peak values of the spatial frequency are out of allowable tolerance range respectively; determining that the image in the frame is of the specific class to be detected if the computed ratio is not within the allowable tolerance range.
In accordance with the present invention, the program may further comprise the step of outputting the result of decision.
In accordance with the present invention, the program may further comprise the step of replacing the specific class of image included in the video subject with other prepared substitute image or images if the specific class of image to be detected is detected in the determining step.
In accordance with the present invention, the program may further comprise the step of eliminating the specific class of image included in the video subject, if the specific class of image to be detected is detected in the determining step.
In accordance with the present invention, the program may further comprise the step of inputting video output from a video display device as the video subject to be inspected.
In accordance with the present invention, the program may further comprise the step of inputting video output from a video playback device as the video subject to be inspected.
In accordance with the present invention, the program may further comprise the step of inputting video output from a TV game machine as the video subject to be inspected.
In accordance with the present invention, the frame is divided into a plurality of blocks, the program may comprise the steps of performing image analysis on each of the blocks in the image analysis step; determining whether or not each of the results obtained from the image analysis on respective block are within an allowable range in the computing step; computing the ratio between the total area of the blocks that have been determined not to be within the allowable range and the area of the frame as the ratio of the part of image being out of the allowable range to the entire image, in the computing step.
In accordance with the present invention, images with patterns of some specific form which may affect the viewing individuals may be automatically detected from within a video stream, by performing image analysis on each image in a frame in a video subject to be inspected with respect to both contrast and spatial frequency thereof, and detecting frames having large image area displayed in which the intensity of the contrast and the frequency range of the peak values of the spatial frequency are out of allowable tolerance range respectively.
In accordance with the present invention, the decisive results of decision means, i.e., the indication of presence or absence of some specific class of image patterns may be output, thereby according to the result output, the specific class of image patterns may be edited or removed by means of image editor later.
In accordance with the present invention, if images of the specific class to be detected are detected by the decision means (or decision step), the images may be automatically substituted by other replacing images previously prepared, so that no human attendant is required to inspect any potentially provocative images. Therefore not only viewers but also video production staff will be protected from potentially harmful images.
In accordance with the present invention, if images of the specific class to be detected are detected by the decision means (step), the viewer as well as video production staff will be protected.
In accordance with the present invention, the output video from a video display device, video playback device, and TV game machine may be inspected.
In accordance with the present invention, the processing time will be shortened by carrying out the image analysis block by block in comparison to the image analysis of the entire frame at once.
In accordance with the present invention, the probability of onset of photosensitive attacks among viewers will be minimized by inspecting for image patterns in the video which are known to cause such photosensitive attacks prior to the on-air broadcast of a program.
Furthermore, these potentially harmful image patterns are automatically checked without human attendance, allowing faster and quicker inspection than the inspection of the prior art by human inspectors, and no deviation of inspection accuracy due to personal error of variation. More importantly, the present invention requires no inspector to be attendant at inspection, allowing production cost to be reduced and workers to be protected from potentially harmful video at the same time. When the video inspecting device is attached or incorporated to commercially available video generating devices such as video tape recorders and TV game machines, the video inspecting device of the present invention enables to checking for and warning of possibly harmful images which may induce photosensitive attacks among viewers.
The above and other objects, effects, features and advantages of the present invention will become more apparent from the following description of embodiments thereof taken in conjunction with the accompanying drawings.